Method of Identifying Duplicate Voice Recording

1. A method of identifying duplicate voice recording, comprising the steps of: a) receiving a plurality of digital voice recordings; b) selecting one of said plurality of digital voice recordings; c) segmenting the selected digital voice recording; d) extracting a pitch value from each segment; e) estimating a total time that voice appears in the selected digital voice recording; f) removing pitch values that are less than and equal to a user-definable value; g) identifying unique pitch values in the result of step (f); h) determining the frequency of occurrence of the unique pitch values; i) normalizing the result of step (h) so that the frequencies of occurrence are greater than zero and less than one; j) determining an average pitch value from the pitch values remaining after step (f); k) determining the distribution percentiles of the result of step (h); l) if additional digital voice recordings are to be processed then returning to step (b), otherwise proceeding to the next step; m) comparing the results of steps (e), (j), and (k) for each digital voice recording processed; and n) declaring the digital voice recordings duplicates that compared to within a user-definable threshold for each of the results of steps (e), (j), and (k).

2. The method of claim 1 , wherein the step of receiving a plurality of digital voice recordings is comprised of the step of receiving a plurality of digital voice recordings in any digital format.

3. The method of claim 2 , wherein the step of segmenting the selected digital voice recording is comprised of the step of segmenting the selected digital voice recording into 16 millisecond segments sampled at 8000 samples per second.

4. The method of claim 3 , wherein the step of extracting a pitch value from each segment is comprised of the step of extracting a pitch value from each segment using any pitch extraction method.

5. The method of claim 4 , wherein the step of estimating a total time that voice appears in the selected digital voice recording is comprised of the step of estimating a total time that voice appears in the selected digital voice recording using the pitch values.

6. The method of claim 5 , wherein the step of removing pitch values that are less than and equal to a user-definable value is comprised of the step of removing pitch values that are less than and equal to zero.

7. The method of claim 6 , further including the step of removing pitch values that vary from one pitch value to the next pitch value by less than or equal to a user-definable value.

8. The method of claim 7 , wherein the step of normalizing the result of step (h) so that the frequencies of occurrence are greater than zero and less than one is comprised of the step of dividing the result of step (h) by the number of pitch values remaining after step (f).

9. The method of claim 8 , wherein the step of determining an average pitch value from the pitch values remaining after step (f) is comprised of the step of determining an average pitch value from the pitch values remaining after step (f) and rounding to the nearest integer.

10. The method of claim 1 , wherein the step of segmenting the selected digital voice recording is comprised of the step of segmenting the selected digital voice recording into 16 millisecond segments sampled at 8000 samples per second.

11. The method of claim 1 , wherein the step of extracting a pitch value from each segment is comprised of the step of extracting a pitch value from each segment using any pitch extraction method.

12. The method of claim 1 , wherein the step of extracting a pitch value from each segment is comprised of the step of extracting a pitch value from each segment using a cepstral pitch extraction method.

13. The method of claim 1 , wherein the step of estimating a total time that voice appears in the selected digital voice recording is comprised of the step of estimating a total time that voice appears in the selected digital voice recording using the pitch values.

14. The method of claim 1 , wherein the step of removing pitch values that are less than and equal to a user-definable value is comprised of the step of removing pitch values that are less than and equal to zero.

15. The method of claim 1 , further including the step of removing pitch values that vary from one pitch value to the next pitch value by less than or equal to a user-definable value.

16. The method of claim 1 , wherein the step of normalizing the result of step (h) so that the frequencies of occurrence are greater than zero and less than one is comprised of the step of dividing the result of step (h) by the number of pitch values remaining after step (f).

17. The method of claim 1 , wherein the step of determining an average pitch value from the pitch values remaining after step (f) is comprised of the step of determining an average pitch value from the pitch values remaining after step (f) and rounding to the nearest integer.